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1. Field of the Invention
The invention relates to communications systems, and in particular, to communications systems that provide voice telephony service using Asynchronous Transfer Mode (ATM).
2. Background
Asynchronous Transfer Mode (ATM) networks are being designed and deployed. ATM is the well-known communications format that is based on a 53-byte cell that includes a five-byte header identifying the virtual connection. ATM cells are designed to carry voice, video, and data traffic within the same communications system. ATM hubs, ATM metropolitan networks, and ATM core networks that transfer ATM cells are well known.
Businesses have increasing communications needs. Most large businesses transmit voice and data traffic over dedicated connections between their various business sites. These large businesses also transmit voice and data over switched connections provided by the Public Switched Telephone Network (PSTN). In addition, these businesses have data networks, such as intranets and frame relay systems.
Residential consumers also have increasing communications needs. These consumers want more communications channels and more bandwidth per channel. The residential consumer also desires more access to media-based services. Despite these technical advances, many residential consumers will still retain their existing telephone devices and will continue to retain conventional telephone service for these devices.
Various ATM deployments are possible to serve business and residential markets, but a problem arises when determining what ATM services should be offered initially and which services added later. This problem is complicated when the various market segments are analyzed. The large business market needs different service offerings than the smaller business market. Both business markets need different service offerings than the residential market.
Deploying a full-service ATM network that serves all markets all at once would be cost prohibitive and extremely complex. A phased approach is needed that provides a migration path from initial service offerings to the full-service ATM network. During the migration, the approach should intelligently offer services that are targeted at the different market segments.
The invention overcomes the above problems by providing a series of architectures that form an incremental migration from initial ATM service offerings to a full service ATM network. The phase I architecture includes several metropolitan ATM networks that are interconnected by a core ATM network. Each metropolitan ATM network includes a service node that controls the ATM network elements that deliver the services.
In Phase I, the business hubs are connected to the metropolitan ATM network over a single ATM connection that integrates voice, data, and Internet traffic. The ATM connection contains Permanent Virtual Connections (PVCs) to various destinations, such as other business hubs, local telephone networks, long distance telephone networks, the Internet, and a frame relay network. In Phase II, the architecture is extended to the smaller business market by providing businesses with PVC-based ATM service using xDSL/ATM connections that are multiplexed at a central office and then provided to the service node over the metropolitan ATM network. In Phase III, a work-at-home hub that uses an xDSL/ATM connections is provided for telecommuting. Phase III also includes the deployment of a session manager and provider agents that interact to interpret user requests and establish the requisite communications paths using Switched Virtual Connections (SVCs). The businesses can replace some or all of their PVC-based service with more efficient SVC-based service. In Phase IV, the architecture is extended to the residential market. A residential hub is provided for residential communications over an xDSL/ATM connection through the central office to the service node. An analog hub is provided for conventional telephone service through the service node.
The first ATM architecture provides ATM PVC-based services to businesses to integrate business communications over a single ATM pipe. The first ATM architecture is comprised of networks, hubs, and Permanent Virtual Connections (PVCs). A core ATM network is connected to a first metropolitan ATM network and a second metropolitan ATM network. The first metropolitan ATM network is connected to a first business hub and a second business hub. The second metropolitan ATM network is connected to a third business hub. The business hubs interwork between ATM and the plurality of different formats, such as ethernet, T1, frame relay, internet protocol, and DS3. The first ATM architecture includes: 1) a first ATM PVC from the it first business hub to the second business hub through the first metropolitan ATM network, 2) a second ATM PVC from the first business hub to a gateway through the first metropolitan ATM network wherein the gateway interworks the second ATM PVC with a connection to a local telephone network, 3) a third ATM PVC from the first business hub to the gateway through the first metropolitan ATM network wherein the gateway interworks the third ATM PVC with a connection to a long distance telephone network, 4) a fourth ATM PVC from the first business hub to a data network through the first metropolitan ATM network and the core ATM network, and 5) a fifth ATM PVC from the first business hub to the third business hub through the first metropolitan ATM network, the core ATM network, and the second metropolitan ATM network.
The second network architecture extends the PVC-based services to the small business market and is created by adding DSL-based multiplexers and hubs. An ATM access multiplexer is connected to the first metropolitan ATM network and a Digital Subscriber Line (DSL) multiplexer is connected to the ATM access multiplexer. A fourth business hub is connected to the DSL multiplexer over a DSL/ATM connection.
The third network architecture is created by adding work-at-home hubs, a session manager, and provider agents. The work-at-home hubs interwork between ATM and a plurality of different formats and are connected to the Digital Subscriber Line (DSL) multiplexer. A provider agent is added to the large business hubs, the small business hubs, the work-at-home hubs, and the PSTN gateway. The session manager interacts with the provider agents to establish SVC-based ATM connections in response to user requirements. In the third network architecture, a business will typically replace some or all of the PVCs used in previous architectures with SVC-based ATM connections because the SVC-based connections are more efficient from a bandwidth and cost perspective.
The fourth network architecture is created by adding a plurality of residential hubs that interwork between ATM and a plurality of different formats and that are each connected to the Digital Subscriber Line (DSL) multiplexer. The fourth network architecture also adds a plurality of analog hubs that interwork between ATM and conventional telephony and that are each connected to the metropolitan ATM network. A provider agent is added to each of the residential hubs and the analog hubs to interact with the session manager to establish SVC-based ATM connections in response to user requests. The fourth network architecture expands the full service ATM network to the residential market, but still provides conventional telephony for those who desire it.